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Spectroscopic identification of ethanol-water conformers by large-amplitude hydrogen bond librational modes.

Andersen, J; Heimdal, Jimmy LU and Wugt Larsen, R (2015) In Journal of Chemical Physics 143(22).
Abstract
The far-infrared absorption spectra have been recorded for hydrogen-bonded complexes of water with ethanol embedded in cryogenic neon matrices at 2.8 K. The partial isotopic H/D-substitution of the ethanol subunit enabled by a dual inlet deposition procedure enables the observation and unambiguous assignment of the intermolecular high-frequency out-of-plane and the low-frequency in-plane donor OH librational modes for two different conformations of the mixed binary ethanol/water complex. The resolved donor OH librational bands confirm directly previous experimental evidence that ethanol acts as the O⋯HO hydrogen bond acceptor in the two most stable conformations. In the most stable conformation, the water subunit forces the ethanol... (More)
The far-infrared absorption spectra have been recorded for hydrogen-bonded complexes of water with ethanol embedded in cryogenic neon matrices at 2.8 K. The partial isotopic H/D-substitution of the ethanol subunit enabled by a dual inlet deposition procedure enables the observation and unambiguous assignment of the intermolecular high-frequency out-of-plane and the low-frequency in-plane donor OH librational modes for two different conformations of the mixed binary ethanol/water complex. The resolved donor OH librational bands confirm directly previous experimental evidence that ethanol acts as the O⋯HO hydrogen bond acceptor in the two most stable conformations. In the most stable conformation, the water subunit forces the ethanol molecule into its less stable gauche configuration upon dimerization owing to a cooperative secondary weak O⋯HC hydrogen bond interaction evidenced by a significantly blue-shift of the low-frequency in-plane donor OH librational band origin. The strong correlation between the low-frequency in-plane donor OH librational motion and the secondary intermolecular O⋯HC hydrogen bond is demonstrated by electronic structure calculations. The experimental findings are further supported by CCSD(T)-F12/aug-cc-pVQZ calculations of the conformational energy differences together with second-order vibrational perturbation theory calculations of the large-amplitude donor OH librational band origins. (Less)
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organization
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type
Contribution to journal
publication status
published
subject
in
Journal of Chemical Physics
volume
143
issue
22
publisher
American Institute of Physics
external identifiers
  • pmid:26671383
  • wos:000367194300035
  • scopus:84951784349
ISSN
0021-9606
DOI
10.1063/1.4937482
language
English
LU publication?
yes
id
20e3ad10-f331-4bb9-9957-948e8faacff6 (old id 8504692)
date added to LUP
2016-01-08 10:24:38
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2017-07-23 03:02:43
@article{20e3ad10-f331-4bb9-9957-948e8faacff6,
  abstract     = {The far-infrared absorption spectra have been recorded for hydrogen-bonded complexes of water with ethanol embedded in cryogenic neon matrices at 2.8 K. The partial isotopic H/D-substitution of the ethanol subunit enabled by a dual inlet deposition procedure enables the observation and unambiguous assignment of the intermolecular high-frequency out-of-plane and the low-frequency in-plane donor OH librational modes for two different conformations of the mixed binary ethanol/water complex. The resolved donor OH librational bands confirm directly previous experimental evidence that ethanol acts as the O⋯HO hydrogen bond acceptor in the two most stable conformations. In the most stable conformation, the water subunit forces the ethanol molecule into its less stable gauche configuration upon dimerization owing to a cooperative secondary weak O⋯HC hydrogen bond interaction evidenced by a significantly blue-shift of the low-frequency in-plane donor OH librational band origin. The strong correlation between the low-frequency in-plane donor OH librational motion and the secondary intermolecular O⋯HC hydrogen bond is demonstrated by electronic structure calculations. The experimental findings are further supported by CCSD(T)-F12/aug-cc-pVQZ calculations of the conformational energy differences together with second-order vibrational perturbation theory calculations of the large-amplitude donor OH librational band origins.},
  articleno    = {224315},
  author       = {Andersen, J and Heimdal, Jimmy and Wugt Larsen, R},
  issn         = {0021-9606},
  language     = {eng},
  number       = {22},
  publisher    = {American Institute of Physics},
  series       = {Journal of Chemical Physics},
  title        = {Spectroscopic identification of ethanol-water conformers by large-amplitude hydrogen bond librational modes.},
  url          = {http://dx.doi.org/10.1063/1.4937482},
  volume       = {143},
  year         = {2015},
}